Pivot arm gear rolling fixture



Feb. 6, 1951 J. J. OSPLACK PIVOT ARM GEAR ROLLING FIXTURE 3 Sheets-Sheet 1 Filed July 8, 1946 INVENTOR Jbaepfi daspzack BY 4... A. ff V p w 1.3 ATTORNEYS Feb. 6, 1951 Filed July 8, 1946 3 Sheets-Sheet 2 31 w l 1: [H I :23 23H i .55 39 33 m 1 I i Q L W&

18 go INVENTOR Jase 1! J. 0.572120 BY M ghxa a H/J ATTORNEYS Feb. 6, 1951 osp 2,540,961

PIVOT ARM GEAR ROLLING FIXTURE Filed July 8, 1946 3 Sheets-Sheet 3 INVENTOR Jasepfi J. asp/act BY M (A4114, H! s ATTORNEYS Patented Feb. 6, 1951 UNITED STATES PATENT OFFICE PIVOT ARM GEAR ROLLING FIXTURE Joseph J. Osplack, Detroit, Mich., assignor to Vinco Corporation, Detroit, Mich.

Application uly 8, 1946, Serial No. 681,932

9 Claims.

tween gears by fiXing one of a mated pair against rotation, meshing the other with it with pitch circles tangent, and then measuring the amount of rotation remaining possible in the unfixed one is also old.

Apparatus for carrying out such methods of gear inspection in the past has comprised a fixed carriage and a movable carriage, each carrying one of the pair of mated gears. The movable carriage was urged towards the fixed carriage by resilient means and was guided in its movement by track means. The two mating gears were rotated and the movement of the movable carriage in either direction along the track means was measured to determine run-out. The gear on the fixed carriage was then locked against rotation and the movable carriage was locked on the track means with the centers of the two gears separated by the sum of their pitch radii. The amount of free movement remaining possible to a tooth of the rotatable gear on the movable carriage at its pitch circumference was then measured to determine backlash. Such apparatus is but poorly suited for carrying out the method attempted because inherent inaccuracies in it gravely affect the reliability of the results, especially in that measurable movements of the carriage will not accurately reflect the run-out because of inevitable inaccuracies in the adjustment of the carriage to the track means.

It is the purpose of my invention to provide improved apparatus for carrying out the method I have just described and to avoid in my improved apparatus the difficulties I have mentioned as limitations on prior apparatus.

In addition to providing a degree of inherent accuracy impossible in gear rolling fixtures of the prior art, a gear rolling fixture constructed accordin to my invention will provide a fast and accurate check both of run-out and backlash on one fixture using a single master gear that is rolled With the production gears to be checked under conditions duplicating their final assembly conditions. Moreover, a gear rolling fixture of my invention will give direct readings, without further computation, of the exact departures from the standard of the gear being inspected. 7

Basically, the apparatus of my invention provides for comparing a production gear with a mating master gear by mounting one gear rigidly against all movement except the ability to rotate, and mounting the other gear on an arm which permits the center of the gear mounted on it to move toward and away from the center of the mating gear, the two gears being held in contact by spring means so that any irregularity of the production gear is capable of direct measurement by dial indicator held against the arm. Measurement of backlash is then obtained by locking the arm at the proper gear center distance and holding one of the gears against rotation while measuring the amount of free rotation permitted to the other gear by the clearance present.

Since all movement that would be imparted to the centers of the gears by reason of run-out is imparted to the dial indicator Without binding or play, except for the almost undetectable play between pivoted members constructed according to modern machining methods, as opposed to the relatively large play inevitable in track mechanisms, the inherent accuracy of such a pivot arm fixture is very great.

For a complete understanding of my invention, including several embodiments thereof, reference is made to the accompanying drawings in which:

Fig. 1 is a plan view of a spur gear rolling fixture constructed according to my invention;

Fig. 2 is a side elevation of the fixture shown in Fig. 1;

Fig. 3 is an end elevation of the fixture shown in Fig. 1;

Fig. 4 is a section taken on the line 4--4 of Fig. 1;

Fig. 5 is a detail section taken on the line 5-5 of Fig.1;

Fig. 6 is a horizontal section taken on the line 6-6 of Fig. 2;

Fig. 7 is a plan view of a gear rolling fixture constructed according to my invention adapted to inspect a worm gear;

Fig. 8 is an elevation of a gear rolling fixture constructed according to my invention adapted to inspect a gear having integral shafts; and

Fig. 9 is a perspective view of a gear rolling fixture constructed according to my invention adapted to inspect an internal gear.

Referring now to Figs. 1 through 6, a pivot arm 6 is pivoted on a base I about a pivot pin 5. Pivot pin 5 is attached to base I as an extension of stud 2 above flange 4 the lower part of which is press fitted into hole 3. Hardened bushing l is inserted in the hub of pivot arm 6 to protect it from wear. Cover flange 8 is fastened to pivot pin by screw 9 to secure pivot arm 6 thereon against vertical movement.

Pivot arm 6 is permitted only limited rotation about the axis of its attachment to pin 5, this rotation being controlled by limit pins 25 and 25 protruding from 'base l adjacentvthe free end of pivot arm 5. I Moreover, this limited rotation can be entirely prevented by lock bolt H) being depressed and engaged in the bore of hardened bushing l8 which is fitted in hole .18 in base I.

Bolt bayonet type slot l2 thereon held in alignment by a dog point screw l3 and lock nutlllin .the free end of pivot arm 6. As will appear more completely later, when the fixture is beingflused 'to measure the run-outf. of a gear being inspect- .:ed,.-shank l l .of .lockbolt ID is entirely withdrawn from bushing I8 and base I and held in this it from entering niore deeply than desired into I bushing 18. In order to protectthe free end of arm 6 against wear, lock bolt ID is carried therein by ahardened bushing l9.

Acam mechanism is provided about bushing is for varying the efiect of stop pins 25 and 25 a and limiting the movement of the free end of pivot arm 6.

This mechanisrncomprises a disc 2% having a hole 2| through it eccentric with,

. and a handle 22 extending from, its outside diameter. 'The inside surface of hole 2! in disc 3 engages snugly but slidably, the outside surface of the portion of bushing 19 emergingwbelow arm 5. Disc and handle are heldvin place by snap retainer ring '23 located in groove 2% on bushing I9 below disc 20.

Intermediate thesaxis about which; pivotz arm 5 is pivoted andits'free end; but rather nearer to pivot pin5, is located shoulder stud 28 for carrying .master gear 27 rotatable thereon. Shoulder stud 28 is carriedin arm 6 by bushing 29.

The ..run-out ,dial :indicator 32 is attached :.to': base I having its indicator. spindle .33, per- -pendicular to and; in contact with arm fiat a spot thedistanceof whichfromthe axis of pivot of arm. a is exactly twice :that of the axis of master gear 2?.

Attached to pivotyarm: 6, atxone. end .and to base i at the other is a tension springxfi i arranged to. urge-pivotiarm, 6. .aboutthe axis of pivot pin 5 against the indicator spindle;33.

- Production geanspindle bracket .35 is slidably mounted on base I and is secured against move:

: mentrin its trackrby means of clamp 38, clamping pressure being obtained by screws. 39. LSlidingspindlbracket 35 is provided with two bush- ,ings 35 ;and 3? 'to accommodate spindles of, production gears of difierentisizes. By means:of-

' adjustment or reversal of spindle bracket 35 on Lbbase l1 andcby choice between spindle bushings -35 and (ii, a wide range of diameters ofproduction V gears canv'be accommodated on the same fixture.

:Backlash dial indicator Allis mounted qonslidable holder ll in guides 42, which are machined zintegraliwithbase l..-.Integral with holder M 1' is an-extension lis having provisionioriscrewfiil on-which finger id-is: pivoted within limits per-- emitted, by undersiZe-pin 5 L; inserted in extension l9 comprises a shankxll havingx-a' spindle against the top of the bushing. Gear .etrmayvbealocked against turning about spindle 5 5 by the action of knurled washer 56 pressing it :against-theintegral spindle flange when hand nut '57 threaded onto clamp screw 51' on spindle fifiiis tightened.

In order to set up the gear rolling fixture illustratedin' Figs. 1-6, for testing a run of production gears of a particular size, a master gear,

::.inachin ed to the; closest :=possible tolerances-" and usually'iduplicating :the; mating:- geart thatwill ":run with the assembled-production gear isiselected. A pitch disc ofthe exactpitch; diameter of the master gear ispla'ced'onshoulder stud'28,

' and a pitch disc; of the. exact pitch. diameter. of

;the;..prcduction;gear to be tested sis plaeeds on 'rspindle 54. Pivot arm 6 is lockedagainst-rota- The location of sliding spindlezbracket 35,1s then set and locked with the circumferences-10f the ;two pitch discs'in contact.

Masten ear. .2 'l-.:is .then. installed one shoulder stud 28, lock bolt IE! is withdrawn and held.;in

- its withdrawnv position by. bayonet slot. .12 ,1. and

means of the camming-action of .disc'29 :.on stop pin 265. -A production. gear. 46 is,,,install ed -0n :spindle -5 i,.-'-but not locked against rotation. wBy

x-reverse action of disc 2il,-,spring.--34 is-permitted toibring; master gear 2'! and.productiongearAAB into meshunder constant zspring load.

, Theygears are-then rolled by 'handn-iandcany run-out or irregularity. of V Tproductionigean 7.45

ment of .the point of contact of indicator. spindle 33 with ipivot arm 6 is twice that of g the center ef-shoulder stud v2 8, dial rindicator 32--must.-be -SPC1311YJ calibrated to; give a direct' reading.

: ln-worderrto -test fbacklashfispivoti arm; is

: holder i l :15: moved forward;in;.=guides= 11212180 .that the point/.4 of; indicator. fi nger M ,inttarsectsthe ..-.pitch. circle or a master gear: 21. .Stop block! 41 is therrlockedain :position :on: slides 142380 .ithat i'the'forward-i travel I-ofslidable: holder 4 l sclimited .bya iathat; position. slidablesholder 4 against stopi-ablock lhby :meanssof the clamping i action. of. thumb screw. daandpin fl.

*P-roduction geariw it qisrturned clockwise runtilrthew-tcoth flankptrmaster, geanfll. aisrinncontact with: the

1 -peint l5 of finger-.44 sand ;the dial, indicator reads fzero. rEroduction'geargllfizis now.--locked sagainst rotation- JOY clam-pings action-- of: hand smut '5'! and the amount of free motion permitted I master -gear": 21:. is read .directly:.;on indicator dial :60.

waBy- -loosening sliding- -block- 4| thropgh :thumb screw 5512116. slidingthe point fli outaofs-inter- -ference with the teeth-of; gear 21; this fbacklash vmeasurementgmay .be repeatedior as. mapyrteeth of a production gear as desired. The provision of stop block 41 facilitates the rapid repetition of a number of backlash readings.

Referring now to Fig. 7, a modified form of the gear rolling fixture previously described is illustrated in which, as before, the base 1 carries a pivot arm 6 pivoted about the axis of a pivot pin 5 and locked on its free end by means of a lock bolt It. The limited travel of the free end of arm 6 is controlled by cam mechanism 22. Base I also carries dial indicator slidably mounted, as already described, for measuring backlash by insertion of the point of a finger 44 between the teeth of a gear carried on pivot arm 6.

A bracket 66 is added to base I, carrying the worm shaft 62 passing through it with a small hand wheel 6'! on one end thereof. The free end of shaft 62 is adapted to pass through the worm 64 to be tested. A taper center collar 65 slides on shaft 62 and through the influence of knurled nut 56 screwed on to the end of that shaft forces Worm 64 into tight engagement with the base of chuck 69.

A dial indicator 32 for measuring run-out is mounted on pivot arm 6 with its indicator spindle 33 in contact with an anvil on base I during the run-out test.

Spring 36, as before, urges arm 6 about pin 5 in the direction to press indicator spindle 33 into engagement with anvil 6|. The method of testing backlash and run-out is, of course, the same with this fixture as with the fixture already described, hand wheel ii'i being provided to facilitate rotation of worm 64.

Referring now to Fig. 8, an embodiment of my invention is shown adapted to test a production spur gear mounted on an integral shaft. In this embodiment, the arrangement of arm 5, look pin it, dial indicator 32 and backlash indicator means (not visible in Fig. 8) is the same as described in connection with Figs. 1 through 6.

Bracket 30 is provided, firmly attached to base I, for carrying the production gear $5 to be tested with integral shaft 95. Base l carries a lower center plug 3! and bracket an carries an upper center 82 exactly aligned with center 8i. Centers 8| and 82 engage the centers of the opposite ends of shaft 95'. Bushing $3 in bracket 80 projects therefrom with an externally threaded portion 85.

The shank of center 32 is journalled in bushing 83 and extends into its threaded portion 85, but with a reduced diameter, thus forming a shoulder at 84 which engages compression spring 88 inside threaded portion 85. A further reduced portion 89 of the shank of center 82 passes through a hole in cap 86 which is screwed down over portion 85 and retains spring 68. The upper end of reduced portion 89 is threaded and carries a knurled nut QB locked by lock nut 9| thereon. The lower surface of the knurled nut 9U rests on arcuate surfaces 92 of a bifurcated lever 93 which is pivotally supported by bracket 9% affixed to bracket 80.

In order to load the fixture with a production gear 95 with integral shaft 95, the operator depresses the outer end of lever 93, thus raising upper center 82. The lower end of shaft @5' is then placed on lower center 8| and upper center 82 is forced into contact with the upper end of shaft 95 by the action of spring 88 when lever 93 is released. The locking and unlocking of production gear 95 against rotation for testing backlash is accomplished by adjusting 6 the force of spring 88 by means of threaded cap 86.

Referring now to Fig. 9, a modified form of the fixture of my invention is shown adapted to test production internal gears. In this case a special bridge type of pivoted arm 6 is employed, rotatable, as before, about a pivot pin 5 carried in base I and having at its free end lock bolt Ill. Dial indicators 32 and 40, are used to check run-out and backlash respectively, as before.

A master spur gear 21 is affixed on pivot arm 5 in this case below, instead of above, the arm to test internal gear 12 and, it will be observed, that in order to facilitate the testing of backlash, spur gear 27 is made Wider to set higher than internal gear 12, thus providing access to the spaces between the teeth of spur gear 27 above the teeth of internal gear 12 for point 65 of finger M, which actuates indicator 40.

To load and unload a fixture constructed as illustrated in Fig. 9, it is necessary that arm 6 be swung completely away from the work. Hence, an additional bushing H is provided in base I so that look bolt H] can be used to anchor arm 6 in a fully retracted position.

Moreover, a rearranged spring means must be provided for urging arm 6 into operative con-- tact with indicator means 32. This comprises a spring 34 carried now on the side of base I and applying pressure to the free end of arm 6 at E2 through means of bellcrank 13. By this means, arm it may be readily engaged and disengaged from the influence of spring 35.

Likewise, means must be provided for retract-- ing master gear 2'! from engagement with internal gears 12 and, on that account, spindle lil carrying master gear 2? is provided with a knob Ti and an internal bayonet groove on spindle l0 similar to that already described in connection with lock bolt Ill, engaging dog head screw 56 which passes through the walls of bushing l5. Ball handle 18 operates clamping means within base I for locking the rotatable mounting to which internal gear 12 is fixed against rota tion during the backlash test.

While I have described my invention in terms of details of particular fixtures, it is not my intention to be limited by those details but rather by the scope of the appended claims.

I claim:

1. A gear rolling fixture comprising a base, an arched arm pivotally carried by said base, a spindle journaled in said arm substantially at the peak of the arch therein, means for mounting a master gear on said spindle within said arch below the peak thereof, means for retracting said spindle to move a gear thereon toward said peak, means for mounting an internal gear to be tested rotatably on said base, spring means urging said arm in a direction to bring a master gear thereon into engagement with a gear to be tested on said base when said spindle is unretracted, and indicator means for precisely measuring the movement of said arm about its pivot when the distance between the axes of a master gear thereon and of a gear to be tested mounted on said base is roughly equal to the algebraic sum of the pitch radii of both gears.

2. A gear rolling fixture according to claim 1 in which the spindle when unretracted is arranged to hold a portion of the width of the teeth of a master gear thereon protruding from engagement with the teeth of a gear to be tested mounted on the base, including a mounting block :'-.s1idably carried-son saidxhase;a'rsecondzindioator means on said block, a pivoted finger mounted oni saidiiblock zwitha one; end. in operatiyeicontact with:- saidr :second: indicator; means, means; for deckingsaidablockin position; means forssecuring .rtherrear to be tested: against-rotatiom-meansior dockingthe; arm against; movement; said :means for locking :said' block in position beingsojspaced inirelation to '1 the center of ;the:.master gearithat the other end 'ofzsaidefinger :can beset-to intersect the pitch circle thereof in the DI'OtIIldifiQfIlOfr. tion: of its .teeth.

.3i.-,-;Asgearr rolling fixture comprising ,aeiaase,

.zanarinpivoted.- near ,oneend thereofroms'aid base,

-meansiorimonnti-ng one 12f. apain ofsmating gears,

.rzconsisti-ngnr one-gear .to. @BitStQdflH-CIDIIB master rotata hiy: omsaid arm means fonmountin :;the other :of said: gears "rotatablyronsaidimbase, spring: means, ,nrgingesaid; arm: in a:;direotion :to

bring: aixgear: thereon: into: engagement with a, ezgeareonz saidrbase; indicator rneans =forrprecise1y measuring the movement of said arm: about its mpivot whenithe distance betweenrtheaxes ofza gearithereonandof agear on saidbaseisrough- PIy-uequaL-tmthe sum ofathepitch radii Tofz'fiaid gears, means 'ifOl". securing one 10f said. gears againstrotatiom means for securingthe :free end -ofrsaid-- arm tosaid: base: in a" position in which i 'the1distanceibetweenhthe axes; of a gear, thereon. andof a: gear on; saidcbase; issprecisely, equal to the sumtof the. pitch sradii' icn said gears, and means for. measuring 4the :residual travel permitted-zone of asaidi gears: when the other is secured against rotation.

4. A gear rolling fixture accordingto-wclaim in which-'theimeans for securing :thewfree, end of thearmfiincludeia lock bolt carried 'by' thetarm near 1 the free end i thereof 'slidable therein. toward and away iromithebase 'an orificerin said.:base

r receiving said lock; bolt when said arm is in the desired position, and means, scarriedbyxysaid arm for securing i. saide 10Ckfzbi01i7. OUtIOf contact with said base.

-- 5. A gear:rollingfixtureaaccordingt ,to claim: 3

including: a pain of stop pins :inithe base spaced apart on opposite sidessof and 'at a distance :from the] pivot of zthe arm, and eccentric. ea'mi'means carried by saidearmiintermediate said stop pins, the degree of e-ecentricitynfusaid cam means heingzsnfiicient-to 'cainssaid arm by reaction against one of said stop means against the resistance of 1: the-sspring;..means;a .;suflicienti distance ,irom a a positionin which ither gearszare :cOmpIeteIy gin ::m'es1rsnnder;;sprin&zur in to: a positionein which ssaidgearsgarezdisengaged. i

6. A gear-Trolling fi-xturesaccordingcto;:clainr 3 irineludinsaan ianvil .,,fixed'=1orri' the; sbasezimwhich 5 ;the;indicatonnneanssisemountedxmnpzthezarnrzin oeerativeccontactwith saidanyil.

7. iktgear roliing fixture according-to claim 3 cin-zwhich the meanszfor; mounting: a gear onvthe base. z'inciude'i a: spindle 'uholden's slidablyr :carried ;:0nrsaid: :base; a. spindle zcarried by said:- holdenrfor is mounting; a; gearetoi; be ;-tested,2;and .iadjnstahle means:for::lockingssaidwsliderirr mositionzomtsaid ;:base.

F SsArgeamrolling fixture accordingrto: claim"? in which the holder is provided withaxpllnality of spindlezgmountings.

9: A gear rolling:fixturetaccordingtto: c1aim 3 azina which theimeansgfiorxmounting aegepar on.:the exhasezinclude a'acenter -.stud"in said:- baseg ia 'zbracket on said, basenyerhandgingsaid; stud;w awrietraeta- .sa'id rstuds a;-;:shank:; on :said: center r-protrnding .throu-gh :saict bracket, adiustab1y-=resi1ient means urging said center towardsaid stud and'iretractingmeansrfor movin -said center away :fromsaid rstud.

.-;-JOSEBI-Ir J. .DSPLAGK.

,REFERENGESiCITED ,UNITED"STATES, BATENTS Number :-Na-me Date 1,222,392 zgGreenet;.a1.. i -1Apr. 10; 1917 .1 233 0214 .ziBarker i Ju1ya*.10,;'1917 l-AA5,6;31 Lotz 'Feb;- 20; 1923 115,554,645 2 OISOIL n i 4 j 'jSeptr122y192 :1 2,335,747 -Pa1quist. .Dec.:14,1?1'943 40 2,340,978 :jOncutt, Feb.: 8, 19144 2,348,712 ,i,Dah1erup May 16;1944 2,381,937 5 Ernst ;:,Aug; 14,719 453 2,399,012 riFarra-nce .Apr.- 23,- 1946 5 "FOREIGN" PATENTS -N umber m Country Date 590,607 n-Germanyn Jan, 5,. 1934 608,163 Germany. -.Jan. 4118,1935

w I? OTHER REFERENCES Gages,Gaging & Inspection,'"I-Iami1ton," The 7 Industrial Press, N.,Y.,.,191,8, page266.

I Machinery, Ju1y1'925, pagei888. 

